Skip to main content
. 2021 Feb 18;10:e63049. doi: 10.7554/eLife.63049

Figure 4. Piezo knockout alters fly feeding behavior.

(A) Fasted wild-type (WT) and Piezo knockout (KO) female flies were given brief access (30 min) to dye-colored food and imaged, scale bar 0.5 mm. (B) Representative images of the crop (arrow) in WT and Piezo KO flies, scale bar 100 μm, (C) Calculated feeding indices (left) and crop sizes (right) from flies in (A). n (feeding index: 17 trials involving 204 flies), n (crop size): 14 flies, mean ± SEM, ***p<0.0001 by unpaired t-test. (D) Body weights of WT and Piezo KO flies fed regular food ad libitum. n (left to right): 32, 34, 33, and 31 trials involving three flies per trial, mean ± SEM, ***p<0.0001 by unpaired t-test. (E) Feeding parameters of fasted WT and Piezo KO male flies were analyzed using the EXPRESSO assay for 30 min after food introduction to determine overall food consumption, feeding duration per bout, and the number of bouts. n: 21 (WT), 22 (PIEZO KO) flies, mean ± SEM, ***p<0.0005, ns: not significant by unpaired t-test. (F) Calculated feeding indices (left) and crop sizes (right) from Piezo rescue and control flies indicated. n (left to right) (feeding index): 29, 22, 30, 22, and 13 trials involving 12 flies per trial. n (crop size): 13, 13, 13, 18, and 16 flies, mean ± SEM, ***p<0.0005, **p<0.005 by ANOVA Dunnett’s multiple comparison test, ns: not significant by unpaired t test. See Figure 4—figure supplements 1 and 2 and source data.

Figure 4—source data 1. Numerical data to support the graph in Figure 4.

Figure 4.

Figure 4—figure supplement 1. Physiological characterization of Piezo knockout flies.

Figure 4—figure supplement 1.

(A) Immunofluorescence for GFP (green) and Elav (magenta) in the hypocerebral ganglion (HCG) of Piezo rescue flies (Piezo knockout; Piezo-Gal4 [59266]; UAS-Piezo-GFP), scale bar 20 μm. (B) Visualizing (left) and quantifying (right) intestinal transit of dye-colored food in wild-type (WT), Drop-dead knockout (Drd KO), and Piezo knockout (Piezo KO) flies. n (left to right): 11, 11, 10, 11, 11, and 10 flies, mean ± SEM, scale bar 200 μm, differences between WT and Piezo KO were not significant by either ANOVA Dunnett’s multiple comparison test or by Fisher's exact test. Measurements of (C) crop size, (D) survival, and (E) fecal spot deposition in WT, Piezo KO, and Drop-dead KO flies. n (left to right) for (C): 13, 16, and 17 flies; for (D): 8, 7, and 7 trials involving 12 flies per trial for WT, Drd KO, and Piezo KO involving 84–96 flies; for (E): 9, 10, and 10 trials involving 10 flies per trial, mean ± SEM, ***p<0.0001; ns: not significant by ANOVA Dunnett’s multiple comparison test; statistical comparison by ANOVA Dunnett’s multiple comparison test of (a)–(c): p=0.0006, of (a, b): p<0.0001. (F) Visualization (left) and quantification (right) of muscle fiber density by a fluorescent Phalloidin conjugate, n: 7 (left) and 10 (right) flies, mean ± SEM, scale bar 100 μm. (G) Quantification of crop cell density based on nuclear staining (TO-PRO-3), n: 7 (left) and 10 (right) flies, mean ± SEM. (H) Measurement of crop size in fasted flies, n: 15 (left) and 9 (right) flies, mean ± SEM. (I) Fasted flies of genotypes indicated were given brief access (30 min) to dye-labeled food at 30°C, and feeding indices and crop sizes were calculated. n (left to right) (feeding index): 14, 15, 15, 15, and 20 trials involving 12 flies per trial. n (crop size): 12 flies, mean ± SEM, ***p<0.0005, ns: not significant by ANOVA Dunnett’s multiple comparison test or unpaired t-test. (J) Fasted flies of genotypes indicated were given brief access (30 min) to dye-labeled food, and feeding indices and crop sizes were calculated. n (left to right) (feeding index): 10, 9, 9, 9, 9, and 9 trials involving 12 flies per trial. n (crop size): 17, 15, 14, 16, 16, and 10 flies, mean ± SEM, ***p<0.0005, ns: not significant by ANOVA Dunnett’s multiple comparison test.
Figure 4—figure supplement 1—source data 1. Numerical data to support the graph in Figure 4—figure supplement 1.
Figure 4—figure supplement 2. Feeding characteristics of Piezo knockout flies.

Figure 4—figure supplement 2.

(A) Feeding indices of male and female wild-type (WT) and Piezo knockout homozygote (Piezo KO) and heterozygote (Piezo KO/+) flies. Flies were fasted, given brief access (30 min) to dye-colored food, and scored. n (left to right) for male: 7, 8, and 5 and female: 13, 13, and 10 trials involving 12 flies per trial, mean ± SEM, **p<0.0005, ***p<0.0001, ns: not significant by ANOVA Dunnett’s multiple comparison test. (B) Piezo KO flies were fasted and then fed with green dye-labeled food; images are depicted of flies with either intact abdomens (left) or bursted abdomens (right).
Figure 4—figure supplement 2—source data 1. Numerical data to support the graph in Figure 4—figure supplement 2.